This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Objective: To investigate potential mechanisms underlying the distribution of virus-specific CTL and virus-producing cells in lymphoid tissues of chronically SIVmac239-infected rhesus macaques and determine whether lentivirus-specific CTL activity is restricted to the extrafollicular compartment of lymphoid tissues in vivo. During HIV (human immunodeficiency virus) infection, an enormous number of cytotoxic T cells are elicited. The role of this cell population is to eliminate virally infected cells. However in spite the large number of HIV specific cytotoxic T cells in the blood, the virus proliferates very efficiently in some part of the lymph nodes. We hypothesize that certain parts of the lymph nodes are immune privileged and cytotoxic T lymphocytes (CTL) are unable to enter to these sites. As a consequence, CTL can kill infected cells in some areas of the lymph nodes, but not others. In this pilot study we are going to infect three animals to determine the distribution of virus-specific CTL and virus-producing cells in lymphoid tissues of chronically SIVmac239-infected rhesus macaques and determine whether lentivirus-specific CTL activity is restricted to the extrafollicular compartment of lymphoid tissues in vivo. PROGRESS: We have established a B-LCL cell line from a selected animal. We are in the process of establishing CD8+ T cell lines. This research used WNPRC Animal Services, CPI and Immunology Services. PUBLICATIONS: None.